How to fix 'AttributeError: 'Mesh' object has no attribute 'active_index''
Replace 

bpy.context.object.data.active_index = 1


with

context.object.data.uv_textures.active_index = 1


The mesh is not a collection and has no active_index, hence the error.

Also consider using the last in the collection rather than by name 'UVMap.001'

context.object.data.uv_textures[-1].name = "Lightmap"


To get on my soapbox replace bpy.context with context as context is passed via the parameters, eg def execute(self, context).